<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
		body, html {
			width: 100%;
			height: 100%;
			display: flex;
			background: #000;
			overflow: hidden;
		}
		div {
			position: fixed;
			margin: 0;
			top:calc(50% - 150px);
			left:calc(50% - 150px);
			width: 300px;
			height: 300px;
			/* css 变量 该变量只能在作用下使用 */
			--colorA: #078eff;
        }
		.div2{
			width: 150px;
			height: 150px;
			top:calc(50% - 75px);
			left:calc(50% - 75px);
			--colorA: #11f249;
		}
		div::before,
		div::after {
				content: "";
				position: absolute;
				top: 0;
				left: 0;
				bottom: 0;
				right: 0;
				border-radius: 50%;
				border-top: 10px solid #fff;
				filter: 
					drop-shadow(0 0 2px var(--colorA))
					drop-shadow(0 0 5px var(--colorA))
					drop-shadow(0 0 10px var(--colorA))
					drop-shadow(0 0 20px var(--colorA));
				animation: rotate 3s infinite linear;
			}
			.div2::after{
				--colorA: #078eff;
			}
			div::after {
				--colorA: #11f249;
				animation-delay: -1.5s;
			}
		@keyframes rotate {
			100% {
				transform: rotate(360deg);
			}
		}
    </style>
</head>
<body>
    <div></div>
    <div class="div2"></div>
</body>
</html>